<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>弹性布局</title>
    <style>
        .fu{
            background-color: #ff0;
        }
        .fu>div{
            width: 200px;
            height: 200px;
            border:5px solid #000;
        }
    </style>
</head>
<body>
<div class="fu" >
    <div class="z1"></div>
    <div class="z2"></div>
    <div class="z3"></div>
</div>
</body>
</html>